Viruses attack our computers in many ways. Some viruses work in the background disabling your antivirus software and corrupting your files but other viruses, such as the fake Security Protection virus take a different approach and pose as a antivirus software designed to protect your computer, when in fact it is installing viruses.
The Security Protection virus is an exceptionally brilliant virus. Once this virus is installed it will do a “full PC scan for viruses” when in fact, it is infecting your computer. This virus will block all other programs from running, even the calculator (smiles).